help on packet format for tcp/ip programming

[Diez B. Roggisch]

> Grant had the right idea, I think, but he failed to actually include a
> byte length in his format. :)  So there's nothing to peek at.  If the
> packing is done like this, instead..
> 
> 
>     struct.pack('!IIL', len(buffer), count, offset) + buffer
> 
> Then it is a simple matter to unpack it once the receiving side, by
> waiting for struct.calcsize('!IIL') bytes, using struct to get
> len(buffer), count, and offset:
> 
>     length, count, offset = struct.unpack('!IIL', bytes)
> 
> And then waiting for `length' more bytes, which will be the buffer.

That was my intention, yes - I thought the header information of the OP
contained a byte count already.
 
> I'm not sure what the original use-case was here.  XML-RPC isn't a good
> transport for arbitrary binary data.  If `buffer' contains text, though,
> that might be a good suggestion.

Certainly XMLRPC isn't too good - and Pyro in many aspects better. AFAIK it
uses pickle, and that means that things should be comparably compact.

Diez